private DTLSRecord CreateRecord(Session session, IHandshakeMessage handshakeMessage, ushort messageSequence)
{
int size = handshakeMessage.CalculateSize(session.Version);
DTLSRecord record = new DTLSRecord();
record.RecordType = TRecordType.Handshake;
record.Epoch = session.Epoch;
record.SequenceNumber = session.NextSequenceNumber();
record.Fragment = new byte[HandshakeRecord.RECORD_OVERHEAD + size];
if (session.Version != null)
{
record.Version = session.Version;
}
HandshakeRecord handshakeRecord = new HandshakeRecord();
handshakeRecord.MessageType = handshakeMessage.MessageType;
handshakeRecord.MessageSeq = messageSequence;
handshakeRecord.Length = (uint)size;
handshakeRecord.FragmentLength = (uint)size;
using (MemoryStream stream = new MemoryStream(record.Fragment))
{
handshakeRecord.Serialise(stream);
handshakeMessage.Serialise(stream, session.Version);
}
if (handshakeMessage.MessageType != THandshakeType.HelloVerifyRequest)
{
session.Handshake.UpdateHandshakeHash(record.Fragment);
}
if (session.Cipher != null)
{
long sequenceNumber = ((long)record.Epoch << 48) + record.SequenceNumber;
record.Fragment = session.Cipher.EncodePlaintext(sequenceNumber, (byte)TRecordType.Handshake, record.Fragment, 0, record.Fragment.Length);
}
return(record);
}
private void SendHandshakeMessage(IHandshakeMessage handshakeMessage, bool encrypt)
{
int size = handshakeMessage.CalculateSize(_Version);
int maxPayloadSize = _MaxPacketSize - DTLSRecord.RECORD_OVERHEAD + HandshakeRecord.RECORD_OVERHEAD;
if (size > maxPayloadSize)
{
}
else
{
DTLSRecord record = new DTLSRecord
{
RecordType = TRecordType.Handshake,
Epoch = _Epoch,
SequenceNumber = NextSequenceNumber(),
Fragment = new byte[HandshakeRecord.RECORD_OVERHEAD + size]
};
if (_Version != null)
{
record.Version = _Version;
}
HandshakeRecord handshakeRecord = new HandshakeRecord
{
MessageType = handshakeMessage.MessageType,
MessageSeq = _MessageSequence
};
_MessageSequence++;
handshakeRecord.Length = (uint)size;
handshakeRecord.FragmentLength = (uint)size;
using (MemoryStream stream = new MemoryStream(record.Fragment))
{
handshakeRecord.Serialise(stream);
handshakeMessage.Serialise(stream, _Version);
}
if (handshakeMessage.MessageType != THandshakeType.HelloVerifyRequest)
{
_HandshakeInfo.UpdateHandshakeHash(record.Fragment);
}
int responseSize = DTLSRecord.RECORD_OVERHEAD + HandshakeRecord.RECORD_OVERHEAD + size;
if ((_Cipher != null) && encrypt)
{
long sequenceNumber = ((long)record.Epoch << 48) + record.SequenceNumber;
record.Fragment = _Cipher.EncodePlaintext(sequenceNumber, (byte)TRecordType.Handshake, record.Fragment, 0, record.Fragment.Length);
responseSize = DTLSRecord.RECORD_OVERHEAD + record.Fragment.Length;
}
byte[] response = new byte[responseSize];
using (MemoryStream stream = new MemoryStream(response))
{
record.Serialise(stream);
}
SocketAsyncEventArgs parameters = new SocketAsyncEventArgs()
{
RemoteEndPoint = _ServerEndPoint
};
parameters.SetBuffer(response, 0, responseSize);
_Socket.SendToAsync(parameters);
}
}
private void SendResponse(Session session, IHandshakeMessage handshakeMessage, ushort messageSequence)
{
int size = handshakeMessage.CalculateSize(session.Version);
int maxPayloadSize = _MaxPacketSize - DTLSRecord.RECORD_OVERHEAD + HandshakeRecord.RECORD_OVERHEAD;
if (size > maxPayloadSize)
{
}
else
{
DTLSRecord record = new DTLSRecord();
record.RecordType = TRecordType.Handshake;
record.Epoch = session.Epoch;
record.SequenceNumber = session.NextSequenceNumber();
record.Fragment = new byte[HandshakeRecord.RECORD_OVERHEAD + size];
if (session.Version != null)
{
record.Version = session.Version;
}
HandshakeRecord handshakeRecord = new HandshakeRecord();
handshakeRecord.MessageType = handshakeMessage.MessageType;
handshakeRecord.MessageSeq = messageSequence;
handshakeRecord.Length = (uint)size;
handshakeRecord.FragmentLength = (uint)size;
using (MemoryStream stream = new MemoryStream(record.Fragment))
{
handshakeRecord.Serialise(stream);
handshakeMessage.Serialise(stream, session.Version);
}
if (handshakeMessage.MessageType != THandshakeType.HelloVerifyRequest)
{
session.Handshake.UpdateHandshakeHash(record.Fragment);
}
int responseSize = DTLSRecord.RECORD_OVERHEAD + HandshakeRecord.RECORD_OVERHEAD + size;
if (session.Cipher != null)
{
long sequenceNumber = ((long)record.Epoch << 48) + record.SequenceNumber;
record.Fragment = session.Cipher.EncodePlaintext(sequenceNumber, (byte)TRecordType.Handshake, record.Fragment, 0, record.Fragment.Length);
responseSize = DTLSRecord.RECORD_OVERHEAD + record.Fragment.Length;
}
byte[] response = new byte[responseSize];
using (MemoryStream stream = new MemoryStream(response))
{
record.Serialise(stream);
}
SocketAsyncEventArgs parameters = new SocketAsyncEventArgs()
{
RemoteEndPoint = session.RemoteEndPoint
};
parameters.SetBuffer(response, 0, responseSize);
_Socket.SendToAsync(parameters);
}
}
private DTLSRecord CreateRecord(Session session, IHandshakeMessage handshakeMessage, ushort messageSequence)
{
if (session == null)
{
throw new ArgumentNullException(nameof(session));
}
if (handshakeMessage == null)
{
throw new ArgumentNullException(nameof(handshakeMessage));
}
var size = handshakeMessage.CalculateSize(session.Version);
var record = new DTLSRecord
{
RecordType = TRecordType.Handshake,
Epoch = session.Epoch,
SequenceNumber = session.NextSequenceNumber(),
Fragment = new byte[HandshakeRecord.RECORD_OVERHEAD + size]
};
if (session.Version != null)
{
record.Version = session.Version;
}
var handshakeRecord = new HandshakeRecord
{
MessageType = handshakeMessage.MessageType,
MessageSeq = messageSequence,
Length = (uint)size,
FragmentLength = (uint)size
};
using (var stream = new MemoryStream(record.Fragment))
{
handshakeRecord.Serialise(stream);
handshakeMessage.Serialise(stream, session.Version);
}
if (handshakeMessage.MessageType != THandshakeType.HelloVerifyRequest)
{
session.Handshake.UpdateHandshakeHash(record.Fragment);
}
if (session.Cipher != null)
{
var sequenceNumber = ((long)record.Epoch << 48) + record.SequenceNumber;
record.Fragment = session.Cipher.EncodePlaintext(sequenceNumber, (byte)TRecordType.Handshake, record.Fragment, 0, record.Fragment.Length);
}
return(record);
}
private IEnumerable <byte[]> _GetBytes(IHandshakeMessage handshakeMessage, bool encrypt)
{
if (handshakeMessage == null)
{
throw new ArgumentNullException(nameof(handshakeMessage));
}
var size = handshakeMessage.CalculateSize(this._Version);
var maxPayloadSize = _MaxPacketSize - DTLSRecord.RECORD_OVERHEAD + HandshakeRecord.RECORD_OVERHEAD;
if (size > maxPayloadSize)
{
var wholeMessage = new List <byte[]>();
var record = new DTLSRecord
{
RecordType = TRecordType.Handshake,
Epoch = _Epoch,
Version = this._Version
};
var handshakeRecord = new HandshakeRecord
{
MessageType = handshakeMessage.MessageType,
MessageSeq = _MessageSequence
};
if (!(handshakeMessage.MessageType == THandshakeType.HelloVerifyRequest ||
(handshakeMessage.MessageType == THandshakeType.ClientHello && (handshakeMessage as ClientHello).Cookie == null)))
{
record.Fragment = new byte[HandshakeRecord.RECORD_OVERHEAD + size];
handshakeRecord.Length = (uint)size;
handshakeRecord.FragmentLength = (uint)size;
handshakeRecord.FragmentOffset = 0u;
using (var stream = new MemoryStream(record.Fragment))
{
handshakeRecord.Serialise(stream);
handshakeMessage.Serialise(stream, this._Version);
}
this._HandshakeInfo.UpdateHandshakeHash(record.Fragment);
}
var dataMessage = new byte[size];
using (var stream = new MemoryStream(dataMessage))
{
handshakeMessage.Serialise(stream, this._Version);
}
var dataMessageFragments = dataMessage.ChunkBySize(maxPayloadSize);
handshakeRecord.FragmentOffset = 0U;
dataMessageFragments.ForEach(x =>
{
handshakeRecord.Length = (uint)size;
handshakeRecord.FragmentLength = (uint)x.Count();
record.SequenceNumber = this._NextSequenceNumber();
var baseMessage = new byte[HandshakeRecord.RECORD_OVERHEAD];
using (var stream = new MemoryStream(baseMessage))
{
handshakeRecord.Serialise(stream);
}
record.Fragment = baseMessage.Concat(x).ToArray();
var responseSize = DTLSRecord.RECORD_OVERHEAD + HandshakeRecord.RECORD_OVERHEAD + x.Count();
if ((this._Cipher != null) && encrypt)
{
var sequenceNumber = ((long)record.Epoch << 48) + record.SequenceNumber;
record.Fragment = this._Cipher.EncodePlaintext(sequenceNumber, (byte)TRecordType.Handshake, record.Fragment, 0, record.Fragment.Length);
responseSize = DTLSRecord.RECORD_OVERHEAD + record.Fragment.Length;
}
var response = new byte[responseSize];
using (var stream = new MemoryStream(response))
{
record.Serialise(stream);
}
wholeMessage.Add(response);
handshakeRecord.FragmentOffset += (uint)x.Count();
});
this._MessageSequence++;
return(wholeMessage);
}
else
{
var record = new DTLSRecord
{
RecordType = TRecordType.Handshake,
Epoch = _Epoch,
SequenceNumber = this._NextSequenceNumber(),
Fragment = new byte[HandshakeRecord.RECORD_OVERHEAD + size],
Version = this._Version
};
var handshakeRecord = new HandshakeRecord
{
MessageType = handshakeMessage.MessageType,
MessageSeq = _MessageSequence
};
this._MessageSequence++;
handshakeRecord.Length = (uint)size;
handshakeRecord.FragmentLength = (uint)size;
using (var stream = new MemoryStream(record.Fragment))
{
handshakeRecord.Serialise(stream);
handshakeMessage.Serialise(stream, this._Version);
}
if (!(handshakeMessage.MessageType == THandshakeType.HelloVerifyRequest ||
(handshakeMessage.MessageType == THandshakeType.ClientHello && (handshakeMessage as ClientHello).Cookie == null)))
{
this._HandshakeInfo.UpdateHandshakeHash(record.Fragment);
}
var responseSize = DTLSRecord.RECORD_OVERHEAD + HandshakeRecord.RECORD_OVERHEAD + size;
if ((this._Cipher != null) && encrypt)
{
var sequenceNumber = ((long)record.Epoch << 48) + record.SequenceNumber;
record.Fragment = this._Cipher.EncodePlaintext(sequenceNumber, (byte)TRecordType.Handshake, record.Fragment, 0, record.Fragment.Length);
responseSize = DTLSRecord.RECORD_OVERHEAD + record.Fragment.Length;
}
var response = new byte[responseSize];
using (var stream = new MemoryStream(response))
{
record.Serialise(stream);
}
return(new List <byte[]>()
{
response
});
}
}
private async Task _ProcessHandshakeAsync(DTLSRecord record)
{
if (record == null)
{
throw new ArgumentNullException(nameof(record));
}
var data = record.Fragment;
if (this._EncyptedServerEpoch == record.Epoch)
{
var count = 0;
while ((this._Cipher == null) && (count < 500))
{
await Task.Delay(10).ConfigureAwait(false);
count++;
}
if (this._Cipher == null)
{
throw new Exception("Need Cipher for Encrypted Session");
}
var sequenceNumber = ((long)record.Epoch << 48) + record.SequenceNumber;
data = this._Cipher.DecodeCiphertext(sequenceNumber, (byte)TRecordType.Handshake, record.Fragment, 0, record.Fragment.Length);
}
using (var tempStream = new MemoryStream(data))
{
var handshakeRec = HandshakeRecord.Deserialise(tempStream);
if (handshakeRec.Length > (handshakeRec.FragmentLength + handshakeRec.FragmentOffset))
{
this._IsFragment = true;
this._FragmentedRecordList.Add(data);
return;
}
else if (this._IsFragment)
{
this._FragmentedRecordList.Add(data);
data = new byte[0];
foreach (var rec in this._FragmentedRecordList)
{
data = data.Concat(rec.Skip(HandshakeRecord.RECORD_OVERHEAD)).ToArray();
}
var tempHandshakeRec = new HandshakeRecord()
{
Length = handshakeRec.Length,
MessageSeq = handshakeRec.MessageSeq,
MessageType = handshakeRec.MessageType,
FragmentLength = handshakeRec.Length,
FragmentOffset = 0
};
var tempHandshakeBytes = new byte[HandshakeRecord.RECORD_OVERHEAD];
using (var updateStream = new MemoryStream(tempHandshakeBytes))
{
tempHandshakeRec.Serialise(updateStream);
}
data = tempHandshakeBytes.Concat(data).ToArray();
}
}
using (var stream = new MemoryStream(data))
{
var handshakeRecord = HandshakeRecord.Deserialise(stream);
switch (handshakeRecord.MessageType)
{
case THandshakeType.HelloRequest:
{
break;
}
case THandshakeType.ClientHello:
{
break;
}
case THandshakeType.ServerHello:
{
var serverHello = ServerHello.Deserialise(stream);
this._HandshakeInfo.UpdateHandshakeHash(data);
this._ServerEpoch = record.Epoch;
this._HandshakeInfo.CipherSuite = (TCipherSuite)serverHello.CipherSuite;
this._HandshakeInfo.ServerRandom = serverHello.Random;
this._Version = serverHello.ServerVersion <= this._Version ? serverHello.ServerVersion : _SupportedVersion;
break;
}
case THandshakeType.HelloVerifyRequest:
{
var helloVerifyRequest = HelloVerifyRequest.Deserialise(stream);
this._Version = helloVerifyRequest.ServerVersion;
await this._SendHelloAsync(helloVerifyRequest.Cookie).ConfigureAwait(false);
break;
}
case THandshakeType.Certificate:
{
var cert = Certificate.Deserialise(stream, TCertificateType.X509);
this._HandshakeInfo.UpdateHandshakeHash(data);
this.ServerCertificate = cert.Cert;
break;
}
case THandshakeType.ServerKeyExchange:
{
this._HandshakeInfo.UpdateHandshakeHash(data);
var keyExchangeAlgorithm = CipherSuites.GetKeyExchangeAlgorithm(this._HandshakeInfo.CipherSuite);
byte[] preMasterSecret = null;
IKeyExchange keyExchange = null;
if (keyExchangeAlgorithm == TKeyExchangeAlgorithm.ECDHE_ECDSA)
{
var serverKeyExchange = ECDHEServerKeyExchange.Deserialise(stream, this._Version);
var keyExchangeECDHE = new ECDHEKeyExchange
{
CipherSuite = this._HandshakeInfo.CipherSuite,
Curve = serverKeyExchange.EllipticCurve,
KeyExchangeAlgorithm = keyExchangeAlgorithm,
ClientRandom = this._HandshakeInfo.ClientRandom,
ServerRandom = this._HandshakeInfo.ServerRandom
};
keyExchangeECDHE.GenerateEphemeralKey();
var clientKeyExchange = new ECDHEClientKeyExchange(keyExchangeECDHE.PublicKey);
this._ClientKeyExchange = clientKeyExchange;
preMasterSecret = keyExchangeECDHE.GetPreMasterSecret(serverKeyExchange.PublicKeyBytes);
keyExchange = keyExchangeECDHE;
}
else if (keyExchangeAlgorithm == TKeyExchangeAlgorithm.ECDHE_PSK)
{
var serverKeyExchange = ECDHEPSKServerKeyExchange.Deserialise(stream);
var keyExchangeECDHE = new ECDHEKeyExchange
{
CipherSuite = this._HandshakeInfo.CipherSuite,
Curve = serverKeyExchange.EllipticCurve,
KeyExchangeAlgorithm = keyExchangeAlgorithm,
ClientRandom = this._HandshakeInfo.ClientRandom,
ServerRandom = this._HandshakeInfo.ServerRandom
};
keyExchangeECDHE.GenerateEphemeralKey();
var clientKeyExchange = new ECDHEPSKClientKeyExchange(keyExchangeECDHE.PublicKey);
if (serverKeyExchange.PSKIdentityHint != null)
{
var key = this.PSKIdentities.GetKey(serverKeyExchange.PSKIdentityHint);
if (key != null)
{
this._PSKIdentity = new PSKIdentity()
{
Identity = serverKeyExchange.PSKIdentityHint, Key = key
};
}
}
if (this._PSKIdentity == null)
{
this._PSKIdentity = this.PSKIdentities.GetRandom();
}
clientKeyExchange.PSKIdentity = this._PSKIdentity.Identity;
this._ClientKeyExchange = clientKeyExchange;
var otherSecret = keyExchangeECDHE.GetPreMasterSecret(serverKeyExchange.PublicKeyBytes);
preMasterSecret = TLSUtils.GetPSKPreMasterSecret(otherSecret, this._PSKIdentity.Key);
keyExchange = keyExchangeECDHE;
}
else if (keyExchangeAlgorithm == TKeyExchangeAlgorithm.PSK)
{
var serverKeyExchange = PSKServerKeyExchange.Deserialise(stream);
var clientKeyExchange = new PSKClientKeyExchange();
if (serverKeyExchange.PSKIdentityHint != null)
{
var key = this.PSKIdentities.GetKey(serverKeyExchange.PSKIdentityHint);
if (key != null)
{
this._PSKIdentity = new PSKIdentity()
{
Identity = serverKeyExchange.PSKIdentityHint, Key = key
};
}
}
if (this._PSKIdentity == null)
{
this._PSKIdentity = this.PSKIdentities.GetRandom();
}
var otherSecret = new byte[this._PSKIdentity.Key.Length];
clientKeyExchange.PSKIdentity = this._PSKIdentity.Identity;
this._ClientKeyExchange = clientKeyExchange;
preMasterSecret = TLSUtils.GetPSKPreMasterSecret(otherSecret, this._PSKIdentity.Key);
}
this._Cipher = TLSUtils.AssignCipher(preMasterSecret, true, this._Version, this._HandshakeInfo);
break;
}
case THandshakeType.CertificateRequest:
{
this._HandshakeInfo.UpdateHandshakeHash(data);
this._SendCertificate = true;
break;
}
case THandshakeType.ServerHelloDone:
{
this._HandshakeInfo.UpdateHandshakeHash(data);
var keyExchangeAlgorithm = CipherSuites.GetKeyExchangeAlgorithm(this._HandshakeInfo.CipherSuite);
if (this._Cipher == null)
{
if (keyExchangeAlgorithm == TKeyExchangeAlgorithm.PSK)
{
var clientKeyExchange = new PSKClientKeyExchange();
this._PSKIdentity = this.PSKIdentities.GetRandom();
var otherSecret = new byte[this._PSKIdentity.Key.Length];
clientKeyExchange.PSKIdentity = this._PSKIdentity.Identity;
this._ClientKeyExchange = clientKeyExchange;
var preMasterSecret = TLSUtils.GetPSKPreMasterSecret(otherSecret, this._PSKIdentity.Key);
this._Cipher = TLSUtils.AssignCipher(preMasterSecret, true, this._Version, this._HandshakeInfo);
}
else if (keyExchangeAlgorithm == TKeyExchangeAlgorithm.RSA)
{
var clientKeyExchange = new RSAClientKeyExchange();
this._ClientKeyExchange = clientKeyExchange;
var PreMasterSecret = TLSUtils.GetRsaPreMasterSecret(this._Version);
clientKeyExchange.PremasterSecret = TLSUtils.GetEncryptedRsaPreMasterSecret(this.ServerCertificate, PreMasterSecret);
this._Cipher = TLSUtils.AssignCipher(PreMasterSecret, true, this._Version, this._HandshakeInfo);
}
else
{
throw new NotImplementedException($"Key Exchange Algorithm {keyExchangeAlgorithm} Not Implemented");
}
}
if (this._SendCertificate)
{
await this._SendHandshakeMessageAsync(this._Certificate, false).ConfigureAwait(false);
}
await this._SendHandshakeMessageAsync(this._ClientKeyExchange, false).ConfigureAwait(false);
if (this._SendCertificate)
{
var signatureHashAlgorithm = new SignatureHashAlgorithm()
{
Signature = TSignatureAlgorithm.ECDSA, Hash = THashAlgorithm.SHA256
};
if (keyExchangeAlgorithm == TKeyExchangeAlgorithm.RSA)
{
signatureHashAlgorithm = new SignatureHashAlgorithm()
{
Signature = TSignatureAlgorithm.RSA, Hash = THashAlgorithm.SHA1
};
}
var certVerify = new CertificateVerify
{
SignatureHashAlgorithm = signatureHashAlgorithm,
Signature = TLSUtils.Sign(this._PrivateKey, this._PrivateKeyRsa, true, this._Version, this._HandshakeInfo, signatureHashAlgorithm, this._HandshakeInfo.GetHash(this._Version))
};
await this._SendHandshakeMessageAsync(certVerify, false).ConfigureAwait(false);
}
await this._SendChangeCipherSpecAsync().ConfigureAwait(false);
var handshakeHash = this._HandshakeInfo.GetHash(this._Version);
var finished = new Finished
{
VerifyData = TLSUtils.GetVerifyData(this._Version, this._HandshakeInfo, true, true, handshakeHash)
};
await this._SendHandshakeMessageAsync(finished, true).ConfigureAwait(false);
break;
}
case THandshakeType.NewSessionTicket:
{
this._HandshakeInfo.UpdateHandshakeHash(data);
break;
}
case THandshakeType.CertificateVerify:
{
break;
}
case THandshakeType.ClientKeyExchange:
{
break;
}
case THandshakeType.Finished:
{
var serverFinished = Finished.Deserialise(stream);
var handshakeHash = this._HandshakeInfo.GetHash(this._Version);
var calculatedVerifyData = TLSUtils.GetVerifyData(this._Version, this._HandshakeInfo, true, false, handshakeHash);
if (serverFinished.VerifyData.SequenceEqual(calculatedVerifyData))
{
this._ConnectionComplete = true;
}
break;
}
default:
{
break;
}
}
}
this._IsFragment = false;
this._FragmentedRecordList.RemoveAll(x => true);
}
private DTLSRecord CreateRecord(Session session, IHandshakeMessage handshakeMessage, ushort messageSequence)
{
int size = handshakeMessage.CalculateSize(session.Version);
DTLSRecord record = new DTLSRecord();
record.RecordType = TRecordType.Handshake;
record.Epoch = session.Epoch;
record.SequenceNumber = session.NextSequenceNumber();
record.Fragment = new byte[HandshakeRecord.RECORD_OVERHEAD + size];
if (session.Version != null)
record.Version = session.Version;
HandshakeRecord handshakeRecord = new HandshakeRecord();
handshakeRecord.MessageType = handshakeMessage.MessageType;
handshakeRecord.MessageSeq = messageSequence;
handshakeRecord.Length = (uint)size;
handshakeRecord.FragmentLength = (uint)size;
using (MemoryStream stream = new MemoryStream(record.Fragment))
{
handshakeRecord.Serialise(stream);
handshakeMessage.Serialise(stream, session.Version);
}
if (handshakeMessage.MessageType != THandshakeType.HelloVerifyRequest)
{
session.Handshake.UpdateHandshakeHash(record.Fragment);
}
if (session.Cipher != null)
{
long sequenceNumber = ((long)record.Epoch << 48) + record.SequenceNumber;
record.Fragment = session.Cipher.EncodePlaintext(sequenceNumber, (byte)TRecordType.Handshake, record.Fragment, 0, record.Fragment.Length);
}
return record;
}
private void SendResponse(Session session, IHandshakeMessage handshakeMessage, ushort messageSequence)
{
int size = handshakeMessage.CalculateSize(session.Version);
int maxPayloadSize = _MaxPacketSize - DTLSRecord.RECORD_OVERHEAD + HandshakeRecord.RECORD_OVERHEAD;
if (size > maxPayloadSize)
{
}
else
{
DTLSRecord record = new DTLSRecord();
record.RecordType = TRecordType.Handshake;
record.Epoch = session.Epoch;
record.SequenceNumber = session.NextSequenceNumber();
record.Fragment = new byte[HandshakeRecord.RECORD_OVERHEAD + size];
if (session.Version != null)
record.Version = session.Version;
HandshakeRecord handshakeRecord = new HandshakeRecord();
handshakeRecord.MessageType = handshakeMessage.MessageType;
handshakeRecord.MessageSeq = messageSequence;
handshakeRecord.Length = (uint)size;
handshakeRecord.FragmentLength = (uint)size;
using (MemoryStream stream = new MemoryStream(record.Fragment))
{
handshakeRecord.Serialise(stream);
handshakeMessage.Serialise(stream, session.Version);
}
if (handshakeMessage.MessageType != THandshakeType.HelloVerifyRequest)
{
session.Handshake.UpdateHandshakeHash(record.Fragment);
}
int responseSize = DTLSRecord.RECORD_OVERHEAD + HandshakeRecord.RECORD_OVERHEAD + size;
if (session.Cipher != null)
{
long sequenceNumber = ((long)record.Epoch << 48) + record.SequenceNumber;
record.Fragment = session.Cipher.EncodePlaintext(sequenceNumber, (byte)TRecordType.Handshake, record.Fragment, 0, record.Fragment.Length);
responseSize = DTLSRecord.RECORD_OVERHEAD + record.Fragment.Length;
}
byte[] response = new byte[responseSize];
using (MemoryStream stream = new MemoryStream(response))
{
record.Serialise(stream);
}
SocketAsyncEventArgs parameters = new SocketAsyncEventArgs()
{
RemoteEndPoint = session.RemoteEndPoint
};
parameters.SetBuffer(response, 0, responseSize);
_Socket.SendToAsync(parameters);
}
}
private void SendResponse(Session session, IHandshakeMessage handshakeMessage, ushort messageSequence)
{
if (session == null)
{
throw new ArgumentNullException(nameof(session));
}
if (handshakeMessage == null)
{
throw new ArgumentNullException(nameof(handshakeMessage));
}
var size = handshakeMessage.CalculateSize(session.Version);
var maxPayloadSize = this._MaxPacketSize - DTLSRecord.RECORD_OVERHEAD + HandshakeRecord.RECORD_OVERHEAD;
if (size > maxPayloadSize)
{
//fragments
return;
}
var record = new DTLSRecord
{
RecordType = TRecordType.Handshake,
Epoch = session.Epoch,
SequenceNumber = session.NextSequenceNumber(),
Fragment = new byte[HandshakeRecord.RECORD_OVERHEAD + size]
};
if (session.Version != null)
{
record.Version = session.Version;
}
var handshakeRecord = new HandshakeRecord
{
MessageType = handshakeMessage.MessageType,
MessageSeq = messageSequence,
Length = (uint)size,
FragmentLength = (uint)size
};
using (var stream = new MemoryStream(record.Fragment))
{
handshakeRecord.Serialise(stream);
handshakeMessage.Serialise(stream, session.Version);
}
if (handshakeMessage.MessageType != THandshakeType.HelloVerifyRequest)
{
session.Handshake.UpdateHandshakeHash(record.Fragment);
}
var responseSize = DTLSRecord.RECORD_OVERHEAD + HandshakeRecord.RECORD_OVERHEAD + size;
if (session.Cipher != null)
{
var sequenceNumber = ((long)record.Epoch << 48) + record.SequenceNumber;
record.Fragment = session.Cipher.EncodePlaintext(sequenceNumber, (byte)TRecordType.Handshake, record.Fragment, 0, record.Fragment.Length);
responseSize = DTLSRecord.RECORD_OVERHEAD + record.Fragment.Length;
}
var response = new byte[responseSize];
using (var stream = new MemoryStream(response))
{
record.Serialise(stream);
}
var parameters = new SocketAsyncEventArgs()
{
RemoteEndPoint = session.RemoteEndPoint
};
parameters.SetBuffer(response, 0, responseSize);
this._Socket.SendToAsync(parameters);
}